Analytic characterization of dynamic optical switching of symmetric self-electrooptic effect devices in extremely shallow quantum wells

An analytical expression of the impulse response of extremely shallow quantum well (ESQW) p-i-n photodiodes is presented. The response function incorporates the effects of the LO phonon scattering rate in the well and the carrier transport coefficients in the continuum states. The result thus obtained has been applied to ESQW symmetric SEEDs (symmetric E-SEEDs) for analyzing the switching characteristics in time. The impulse response function is derived, and the circuit equations of symmetric SEEDs (S-SEEDs) are examined. Specifically, it is pointed out that the RC time constant inherent in S-SEEDs speeds up the down-switching (from reverse to forward), while delaying the up-switching (from forward to reverse) of the two diode voltages involved. The analytic solutions of the two diode voltages in symmetric E-SEEDs are given as a function of time during the dynamic optical switching